Update, December 1, 2pm: This issue has been resolved.
We are currently experiencing an issue with the Classic Catalogue. It is safe to use and continues to operate normally but anyone trying to access it will see a security error that they need to bypass in order to use it.
Library staff and McGill IT are working to fix technical issues that are causing the security error.
We apologize for any inconvenience while we work to resolve this issue as quickly as possible.